

Did you know a small 8′ x 10′ area of roof will generate 50 gallons of water during a 1-inch rain event?
Historically and in many developing countries still today, many homes use a cistern to capture rainfall for household purposes. Rainwater harvesting, like the cistern, is the process of collecting rainwater and storing it for later use. Storage methods range from small barrels to large underground storage tanks. It is a valuable water management practice that is greatly underutilized.
Rain barrels are a simple and cost-effective way that you can recycle stormwater generated from your house and put it to good use. Rain barrels are easy to build and install and can provide many benefits.
How to use collected rainwater
- Water plants, gardens, and lawns
- Rinse out recyclables before placing them in the recycle bin
- Wash exterior fixtures like windows, mailboxes, & dog houses
- Water collected in rain barrels is non-potable and should not be used as drinking water
Where to use rain barrels
Rain barrels can be used to collect water from downspouts on your house, garage, or shed. A typical rain barrel captures 50 to 60 gallons, but they can come in all different sizes and designs. An 8′ x 10′ area of roof can generate 50 gallons of water during a 1-inch rain event. When choosing a downspout location for your rain barrel, consider how much roof area will be contributing water.
Harvested Water (gallons) = Rooftop Surface Area (square feet) x Average Rainfall event (inches) x 0.623
For more water collection potential, choose a larger rain barrel size. You can also connect multiple smaller rain barrels together for more storage capacity.


How to Build a Rain Barrel

Rain Barrel Rebate Programs

Get Inspired! Find Rain Barrel Ideas
Additional Resources
How to Host A Rain Barrel Workshop for your Group or Community
Iowa Stormwater Education Partnership
Find materials to build a rain barrel – Iowa Waste Exchange Database
Find materials to build a rain barrel – Habitat for Humanity ReStore
Habitat for Humanity Tool Lending Library